explain_ftell_or_die(3)

get stream position and report errors

Section 3 libexplain-dev bookworm source

Description

explain_ftell_or_die

NAME

explain_ftell_or_die - get stream position and report errors

SYNOPSIS

#include <libexplain/ftell.h>
long explain_ftell_or_die(FILE *fp);
long explain_ftell_on_error(FILE *fp);

DESCRIPTION

The explain_ftell_or_die function is used to call the ftell(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_ftell(3) function, and then the process terminates by calling exit(EXIT_FAILURE).

The explain_ftell_on_error function is used to call the ftell(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_ftell(3) function, but still returns to the caller.

The fp, exactly as to be passed to the ftell(3) system call.

RETURN VALUE

The explain_ftell_or_die function only returns on success, see ftell(3) for more information. On failure, prints an explanation and exits, it does not return.

The explain_ftell_on_error function always returns the value return by the wrapped ftell(3) system call.

EXAMPLE

The explain_ftell_or_die function is intended to be used in a fashion similar to the following example:

long result = explain_ftell_or_die(fp);